In a presentation at this summer’s National Clean Energy Summit convened by the University of Nevada Las Vegas, Sen. Harry Reid (D-NV), and the Center for American Progress Action Fund, Dr. Chu described why he has moved from his background in experimental quantum physics to tackling global warming:

Consider this. There’s about a 50 percent chance, the climate experts tell us, that in this century we will go up in temperature by three degrees Centigrade. Now, three degrees Centigrade doesn’t seem a lot to you, that’s 11° F. Chicago changes by 30° F in half a day. But 5° C means that … it’s the difference between where we are today and where we were in the last ice age. What did that mean? Canada, the United States down to Ohio and Pennsylvania, was covered in ice year round.

Five degrees Centigrade.

So think about what 5° C will mean going the other way. A very different world. So if you’d want that for your kids and grandkids, we can continue what we’re doing. Climate change of that scale will cause enormous resource wars, over water, arable land, and massive population displacements. We’re not talking about ten thousand people. We’re not talking about ten million people, we’re talking about hundreds of millions to billions of people being flooded out, permanently.

As Dr. Chu explains in the above video, the optimal way to reduce greenhouse emissions is to waste less energy, by investing in energy efficiency. He demolished the myth that we can’t reduce our use of energy without reducing our wealth by offering numerous counterexamples, or, in his scientist’s jargon, “existence proofs.” Applause broke out when he described how companies, after claiming efficiency gains and lowered costs were impossible, “miraculously” achieved them once they “had to assign the jobs from the lobbyists to the engineers.”

Chu continued by discussing what he has done to develop “new technologies to transform the landscape.” He discussed the Helios Project, the research initiative Berkeley Lab launched for breakthrough renewable energy and efficiency technology. In addition to research into energy conservation, Berkeley Lab researchers are pursuing nanotech photovoltaics, microbial and cellulosic biofuels, and chemical photosynthesis.

Dr. Chu concluded his address with a reminder why this challenge is so important:

I will leave you with this final image. This is – I was an undergraduate when this picture was taken by Apollo 8 – and it shows the moon and the Earth’s rise. A beautiful planet, a desolate moon. And focus on the fact that there’s nowhere else to go.